We put the Wood Vinyl Plank down on an underlayment sheet which sits on concrete. The floor went in and looks fine.Unfortunately the multi trim is another story. Our application is vinyl wood plank meets carpet. We needed a transition strip that covers the gap between carpet and the vinyl plank. The instruction sheet given to me by lumber liquidators says to leave 1" gap and the moulding is 2" thick. It is NOT. It is 1 5/8" wide. It also clearly states 8 dowels are included to secure molding to floor. Wrong, 6 dowels are included. So instead of a dowel every 11.5" like instructions say, you have one every 18". Not enough to keep molding secure. It moves around a lot when touched with feet. Seems cheap!Overall very disappointed. If you buy this do not leave 1" gap between floor surfaces like the instructions indicate. Also, get your hands on extra dowel. Only 6 per pkg, not 8.